Electric traction

[colchesterken]

I was reading that it needs 2000amps to start a loaded tube train that got me thinking ( oh dear )
How many amps would be needed to start a loaded cl90 or 91.I know that if you halve the voltage you double the amps, what is the ampage in the knitting,and what is the voltage of the motors ?
Using the tube as a starting point I guess the overhead is about 70-100amps
Anyone any thoughts. (yes I know I need to spend more time watching daytime tellie)

 

[HSTEd]

Well if we assume the nominal 25000V in the supply (not the maximum 27kV or minimum ~19.5kV) then if the driver of a Class 91 goes directly to full power (which would spin the wheels like anything but nevermind) it could draw a maximum of ~200amps.

It will ofcourse be far less than this, but still it shows how much smaller it is than third rail currents.

 

[captainbigun]

Nominal allowance on the OHL is 10%, however it has been seen around 12kV and as high as 30kV. Some traction really does object to this....

Classes 89/90/91/92 are rated at 200A. They will draw this when maximum TE is being put down.

TM2201A (89), GE412 (87/90) and GE426 (91) are all rated around 1000V/1000A.